Abrasive belt swing grinder



Oct. 28, 1947. H. R.- HERCHENRlDp-:R 2,429,621 v V ABRASIVE BELT SWING GRINDER I Y Filed June 4, 1945 2 sheets-sheet 1 I v y 074 eys Oct. 28, `1947. H. RQHERCHENRIDER ABRASIVE BELT SWING GRINDER 2 Sheets-Sheet 2 Filed June 4, 1943 Zip-ue 76507 Patented Oct. 28, 1947 Henry R. Herchenrider, Mount Lebanon, Pa., as

signor to Minnesota Miningv & Manufacturing Company, St. Paul, Minn., a corporation of Delaware Application YJune 4, 1943, Serial No. 489,628

This' invention relates to 'a grinding and polishing apparatus. More particularly, it is concerned with a swing-frame grinder adapted to employ an .abrasive belt.

A common type of swing-frame grinder is made up of an abrasivelwheel or spindle mounted on the end of a horizontal support. This support in turn is fastened to a vertical member which is overhead, thus permitting the grinder to be moved back and forth over the work readily by means of two handles-' These machines are not adapted to the use of `an abrasive belt because when suspended from the horizontal support in a balanced position, the points of suspension are usually so located on the frame of the swingframe grinder to prevent the changing of an abrasive belt.

In U. SQ Patent 2,070,257 to Coates, a portab-le type polishing and grinding machine adapted to be suspended from an overhead yoke hanger was proposed for use with an abrasive belt. This apparatus includes spaced motors carrying the pulleys on which the abrasive belt is mounted, the motors being arranged for movement toward and 4from each other to tighten Vor loosen the belt'. Each motor has a telescoping engagement with a sliding keyed connection to preventl angular displacement of one vmotor with respect to the other. Resilient means, preferably compressed air, within the telescoped members yieldingly,v urges the motors apart to put the belt under tension. The yoke hanger is entirely open at one side to permit changing of the abrasivev belt. This apparatus is a complicated mechanism requiring two motors, compressed air, etc. which is diicult to suspend in a balanced position because of the single pivot point by which the yoke hanger is attached to the machine. The single point of suspension limits the size and Weight of the machine that may be suspended, and reduires an additional mechanism to lock the machine in upright position.

An object of this invention is to devise a compact swing-frame grinder which is balancedly supported in upright position by a yoke tiltably attached to the framework of the grinding machine at a plurality of pivot points. Another object is to devisea grinding and polishing machine in which the means of power, preferably a motor, is positioned in the framework of the machine, generally intermediate between at least one idler roll andthe pressure roll. Another object is-tov devise a hand-directable grinding and polishing machine adapted to employ an abrasive belt which contains means which will `least one idler roll vand -a pressure roll, themotor being adapted'to provide drivingpower to the pressure roll, and means fortransferring the weight of the suspended'framework from one of the pivot: points to al temporary point of suspension sofas to provide an opening through whichthe abrasive belt maybe'changed. Such means `may comprise ahook-shaped handle pivotedto the yoke, albase plate affixed to the framework, and .a hook-receiving latch pivoted vto the base plate, the hook-shaped handle being adapted tofbe used' as' an eccentric when positionedin -the'hook-receiving latchso as to permit removal of the pivot-receiving bar from the pivot point when the weightof the frame-work is distributed from the pivot pointto the handle eccentric.

In order to illustrate the invention, a specific embodiment thereof is shown in the accompanying drawings.V

Figure 1 isa side elevation view of a swingframe grinder with abrasivebelt mounted.

rFigure 2 is atop plan view'with the top guard removed. Figure 3 is a-cross-sectional'view taken along thev lines 3-3 showing the handle positioned in conformity with the' yoke and the dotted lines showing the handle 'eccentric in operating position.

Referring to the drawings in detail, the numeral ill designates in general thev swing-frame grinder. This grinder I0 consists of a tubular frame' il upon one end of which is mounted a pair of idler rolls or pulleys I2and I3, by means of pivoted brackets I4 and I5 aixed to a plate @Si by means'of bolts I6. The plate 6l in turn is affixed to the frame Il, for exampleby welding. The idler rolls `I2` and I3 are ball-bearing mounted at Il'and Il on axles or shafts I8 and I8 in the brackets i4 and l5, respectively.. The bracket i4 is pivoted'on' aA vertical pivot shaft I9 for belt alignment. When the bracket I4 is moved around its pivot shaft I9 by turning a rod 2D, it positionsv the idler roll I2 around the vertical pivot shaft I9 so as to position the abrasive belt 22 in the correct operating position at the center of the pressure roll 39. The bracket I is pivoted on Aa horizontal pivot shaft I9' for belt tensioning. The rod 2| is connected to a universal joint 24', which moves a shaft 21', which has a fine micrometer screw or screw thread 25 that is threaded into a guide block 2'5, which in turn is affixed to the bracket I5. The tension of the belt 22 may be adjusted by turning the rod 2 I. The rods 2D and 2l are supported by means of iron brackets 23 afiixed to the frame I I.

A motor 28 is mounted to the frame Il by means of angle irons 29, which in turn are bolted to vertical plates 30 afxed to the frame, as illustrated in Figure 3.

The motor 28 drives a drive shaft 3l that in turn drives a shaft 33, through a coupling 32. The shaft 33 extends into a set of mitre gears (not shown). These mitre gears are used to change the direction of motion so as to drive a shaft 34 perpendicular to the path of the belt 22. A pair of V-belt sheaves 35 are keyed to the shaft 34, and they in turn drive the V-belt sheaves 35, through a V-belt drive 31. The V-belt sheaves 36 are keyed to a pressure roll shaft 38 and positioned on each side of a pressure roll or contact roll 39, which carries the abrasive belt 22. The pressure roll assembly is mounted to the back plate of the frame 4U by means of brackets 4I bolted to the frame. Hollow tubular handle bars 42 are slipped over stationary bars 43 which are afIiXed to the pressure roll assembly. These handle bars may be used to manually direct the grinder I9, and in addition, they can be used to increase the leverage about the pivot points 45 and 45. If desired, sheet metal guards (not shown) may be placed over the V-sheave assembly and belt. A top guard 44 is shown in Figure 1 positioned over the abrasive belt 22.

On each side of the frame II near the center of the grinder I9 is mounted a pair of pivots 45 and 46. These points or pivots consist of small flanged rods or bars, which in turn are attached to base plates 41 and 48, which are attached to the frame Il. The swing-grinder I Il is mounted to a hoist or trolley (not shown) by means of a tiltable U-shaped tubular bar 49 which forms a yoke. This yoke 49 is carried on guide rolls 5i! of a triangular metal pulley 5|, which is suspended from the hoist by a swivel eye 52. rIhe yoke 49 may be locked in place in the pulley 5I by means of a removable bolt or pin 53. One of the ends or arms 54 of the U-shaped bar 49 is attached to the pivot 45 by means of a clamp 55 which serves as a bearing for the pivot so as to allow movement of the yoke circumferentially around the pivot point 45. The other arm of .the yoke carries a pivot-receiving portion 51 which is hinged to the main portion of the yoke arm. The base plate 48 carries a hook-receiving latch 55. A handle or lever 59 is pivoted on the yoke 49 in close proximity to the pivot point 46. The alternate end of the handle 59 is shaped in the form of a hook 59 which can be used as an eccentric when positioned in the hook-receiving latch 58, The handle 59 when not in use is positioned to conform with the yoke 49. When the handle is in use as an eccentric, as shown in Figure 3 in dotted lines, the pivot-receiving bar 51 can be removed from the pivot point 46 and swung outwardly and upwardly when the weight of the grinder Il] is distributed from the pivot point 45 to the handle eccentric, as illustrated in Figure 3 in dotted lines.

If it is desired to place an abrasive belt 22 upon the swing-frame grinder I 9, while it is in suspended position, it may conveniently be done by threading the belt 22 in the form of a loop through the bar or yoke 49, whereupon the bottom portion of the belt 22 may then be slipped or positioned between the base plate 48 and the pivot-receiving bar 51 immediately below the hook-receiving latch 58, as shown in Figure 3. The hook end 60 of the handle 59 may be inserted in the hookreceiving latch 58 to serve as an eccentric, and the weight of the grinder I9 distributed from the pivot point 46 to the handle eccentric, as illustrated in Figure 3 in dotted lines. The pivot-receiving bar 51 may then be swung outwardly and upwardly from the pivot point 45, and the bottom portion of the abrasive belt may be slipped around the bottom of the grinder ID. The pivotreceiving bar 51 may then be repositioned around the pivot point 45, and the weight of the grinder I9 reshifted or redistributed from the handle eccentric to the pivot-receiving bar 51, and the handle 59 positioned in conformity with the yoke. The abrasive belt 22 may then be positioned around the pressure roll 39 and the idler pulleys I2 and I5 and the tension adjusted by means of the rod 2i.

Ordinarily, if an abrasive belt is worn out, it will be removed by simply cutting or tearing the belt. However, in the event it is desired to remove the belt without damaging it, the reverse cycle above described may be used.

An equally convenient method of placing an abrasive belt 22 upon the grinder I0, is to thread the bottom portion of the abrasive belt 22 under the suspended grinder IU, and position it around the bottom of the pressure roll 39 and the idler roll I3. The hook end 5l) of the handle 59 may then be inserted into the hook-receiving latch 58 to serve as an eccentric, and the weight of the grinder E9 distributed from the pivot point 46 to the handle eccentric, as illustrated in Figure 3 in dotted lines. The pivot-receiving bar 51 may then be swung outwardly and upwardly from the pivot point 4G, and the top portion of the belt 22 may then be slipped above the pivot point 46, through the opening between the base plate 43 andthe pivot-receiving bar 51 made by the pivoting of the pivot-receiving bar 51. The pivotreceiving bar 51 may then be repositioned around the pivot point 45, and the weight of the grinder lil reshifted or redistributed from the handle eccentric to the pivot-receiving bar 51, and the handle 59 positioned in conformity with the yoke. The top `of the abrasive belt 22 may then be 'positioned around the pressure roll 39 and idler pulleys i2 and I3 and the tension of the belt adjusted by means of the rod ZI. If desired, the reverse cycle of this operation may be used to remove the belt 22 from the grinder.

If it is desired to tilt the grinder at an angle, thus tilting the work surface of the abrasive belt, it may be conveniently done by removing the pin 53 from the triangular metal pulley 5I, and turning the yoke 49 to the right or left to the desired angle. Generally, however, the grinder will be operated in an upright or horizontal position, and the pin 53 may be inserted in the pulley 5I to lock the yoke 49 securely, and prevent the machine from moving from the upright position.

The pressure roll 39 may be of any type of roll suitable for bringing the abrasive into contact agganci s with the material to be Aground or polished. However, it :is -preterable-tofu'se-fthe pressure 1 rolls :disclosedlin Patents Nos. '2,1115311128 and-2;l62,2.79 Aissued Atome, A*and-'n `1my .co-'pending application S.1;N.-=4811;537,.medi-April `.2, 219143. y

@ther advantages and Vtorrns .ofapparatus'fwill ibefapparent -f rom theoregoingdisclosure to Athose 'skilled -in fthe lar-t, .and while aspecic embodimenthas been used-.toitiflhistrateamy invention, it fis `Jtobe understoodthatthe invention isfnot-'limiited to this embodiment, but isdefhled by'ithe lappended claims.

What I claim is:

1. A grinding machine comprising a frame, a plurality of rolls including a presser roll mounted in the frame for supporting an endless abrasive belt, means for driving the belt, frame-supporting pivots on the frame, a frame-supporting yoke having arms that straddle a flight of the belt, bearings in the arms of the yoke adapted to receive the pivots and thereby to support the frame pivotally, means in the yoke for opening a portion of it temporarily to permit insertion -or withdrawal therefrom of a ight of an endless belt and means for temporarily supporting the frame While the yoke is temporarily open.

2. A grinding machine comprising a frame, a plurality of rolls including a presser roll mounted in the frame for supporting an endless abrasive belt, means for driving the belt, frame-supporting pivots on the frame, a frame-supporting yoke having arms that straddle a. iiight of the belt, bearings in the arms of the yoke adapted to receive the pivots and thereby to support the frame pivotally, means in the yoke for opening a portion of it temporarily to permit insertion or withdrawal therefrom of a iiight of an endless belt and means for temporarily supporting the frame by the remaining portion of the yoke while the said first portion is temporarily open.

3. A grinding machine comprising a frame, a plurality of rolls including a presser roll mounted in the frame for supporting an endless abrasive belt, means for driving the belt, frame-supporting pivots on the frame, a frame-supporting yoke having arms that straddle a flight of the belt, bearings in the arms of the yoke adapted to receive the pivots and thereby to support the frame pivotally, the bearing-containing portion of one arm being hinged to the main portion of that arm to permit the hinged portion to be disengaged from the pivot that is normally held in the bearing and to be swung open to permit insertion or withdrawal from the yoke of a flight of an endless belt, and means for temporarily supporting by the main portion of the yoke arm the weight of the frame that is normally supported by the hinged portion.

4. A grinding machine comprising a frame, a plurality of rolls including a presser roll ,mounted in the frame for supporting an endless abrasive belt, means for driving the belt, frame-supporting pivots on the frame, a frame-supporting yoke having arms that straddle a iiight of the belt, bearings in the arms of the yoke adapted to receive the pivots and thereby to support the frame pivotally, the bearing-containing portion of one arm being hinged to the main portion of that arm to permitthe hinged portion to be disengaged from the pivot that is normally held in the bearing and to be swung open to permit insertion or withdrawal from the yoke of a flight of an endless belt, a temporary frame-supporting means on the frame spaced from the said pivot, la :temporary `iirame-supporting imeans fon the said main portion of the .yoke arm, rand means -connectingzthe two said itemporary framesupporting means to support the frame while the said hinged portion of "theyoke arm is open.

5. A grinding machine .comprising ia vframe, a plurality of rolls including a presser roll mounted in the `frame for supporting an ,endless abrasive belt, means for driving the belt, frame-supportingpivots on the frame, a frame-supporting :yoke lhaving ,arms .that .straddle :a flight .of the belt, bearings in the arms of the yoke adapted to receive the pivots and thereby to support the frame pivotally, the bearing-containing portion of one arm being hinged to the main portion of that arm to permit the hinged portion to be disengaged irom the pivot that is normally held in the bearing and to be swung open to permit insertion or withdrawal from the yoke of a, flight of an endless belt, a hook-receiving element attached to the frame and a lever pivoted to the said main portion of the one yoke arm, one end of the lever being in the form of a handle and the other a hook positioned to permit its engagement with the said hook-receiving element and upon pressure against the handle to support the weight of the frame that is normally supported by the said hinged portion of the one yoke arm.

6. A belt grindercomprising an approximately horizontally disposed frame, a motor borne by said frame, a presser roll rotatably mounted on a horizontal axis at the front of said frame, means extending from said motor to said roll for driving the latter, a lower idler roll bracket mounted on the rear of said frame for rotary movements on a horizontal axis parallel to the axis of rotation of its idler roll, an upper idler roll bracket mounted on the rear of said frame for rotary movements on a vertical axis perpendicular to the axis of rotation of its idler roll and lying midway between the ends thereof, idler rolls borne by each of said brackets, respectively, for rotation on horizontal axes, a grinding belt extending around said presser and idler rolls, means for rotating said lower bracket about its said horizontal axis to vary the spacing oaf the axes of said rolls, and means for rotating said upper bracket about its said vertical axis to control the tracking of said belt.

'7. The device of claim 6 in which each of the two means for rotating the brackets are provided with operating members that' extend to the front of said frame.

8. A swing grinder comprising an elongate frame adapted to be approximately horizontally disposed when in use, a lower idler roll bracket pivotally mounted on the rear of the frame for rotary movement about an approximately transverse horizontal axis, an upper idler roll bracket pivotally mounted on the rear of the frame for rotary movement about an approximately vertical axis, idler rolls mounted in each of the brackets, respectively, for rotation on approximately transverse horizontal axes, a presser roll mounted on the front of the frame for rotation on an approximately transverse horizontal axis, an abrasive belt extending longitudinally of the machine around the idler and presser rolls, means for rotating the lower bracket about its said horizontal axis for varying the distance between the rolls to control the tension of the belt, means for rotating the upper bracket about its said Vertical axis to control the tracking of the belt, a motor within the frame and means extending from the motorto the presser roll for driving the Number -presser roll and the belt. Y 810,037 HENRY R. I-IERCHENRIDER. 1,365,583 2,279,732 REFERENCES CITED 5 2,070,257 The folowing references are of record in the 2,333,507 fue of this patent; 215%??? UNITED STATES PATENTS 1,4372114 Number Name Date 10 1.974,806 2,280,762 Phipps Apr. 21, 1942 1,288,908

8 Name Date Clemons Jan. 16, 1906 Brown Jan. 11, 1921 Fowler Apr. 14, 1942 Coates Feb. 9, 1937 Bair et al. Nov. 2, 1943 Price et a1. Oct. 8, 1935 Driver Feb. 8, 1898 Gruenhagen Dec. 5, 1922 Curtis et al. Sept. 25, 1934 Johnson Dec. 24, 1918 

